The present invention relates to an improved system and method for activation of a vehicle horn or other vehicle functions and for detecting the weight of a person seated within a motor vehicle.
Current horn sensor designs have a large variability in force over the operating area of the sensor. In other words, the force needed to activate the horn may vary greatly between two different points on the horn sensor contact surface. Even at a given location on the horn sensor contact surface, the force required may also vary (e.g. two to seven pounds) over operating conditions, such as temperature, etc. Further, the sensitivity level of the sensor cannot be adjusted easily without significant time and expense for retooling.
Current vehicles include an airbag for the driver as well as the front seat passenger. The danger that the passenger side airbag poses to infants in car seats and small children as well as small adults has been well documented. Manufacturers have sought to develop systems that would disable the passenger side airbag if the weight on the passenger seat is below a given threshold, thereby indicating either the presence of an individual for whom the airbag would be dangerous or the absence of any passenger at all.
One known system, described and claimed in U.S. Pat. No. 5,739,757, entitled “Vehicle Passenger Weight Sensor,” the assignee of which is the assignee of the present invention, uses a magnetostrictive sensor to measure strain on a wires under the cushion of the seat to determine the weight of a person or thing seated. However, this design may not always measure all of the weight on the seat, which may not be transmitted to the wires under the cushion, depending upon the position of the passenger.